1. Field of the Invention
The present invention relates to the field of automated packaging systems. More particularly, the present invention relates to the field of carrier tape packaging systems.
2. Description of the Prior Art
Generally, small components, such as integrated circuit (IC) chips or die sawn from silicon or GaAs wafers are particularly susceptible to damage by mechanical forces and by electro-static discharge. Mechanical stress to the IC chip or die can cause structural damage, including cracking, chipping and breaking of these extremely fragile and brittle components, thereby causing both patent and latent defects in their functionality. Therefore, it would be a significant advantage if the component such as IC wafer die and other devices with smooth flat surfaces could be packaged to facilitate automatic handling and removal from the package when needed in a manner to protect and avoid damage to these delicate components and simultaneously minimize electro-static charge buildup during automatic handling.
Carrier tape packaging systems are known in the prior art. Existing carrier tape packaging systems typically include an elongated double sided and flexible carrier tape which is made of paper or plastic. The flexible carrier tape has a multiplicity of punched cavities which are utilized for retaining small electronic components, such as surface mount devices (SMDs). Generally, heat sealed cover tapes, one on each side of the punched carrier tape, are used to retain components within the punched cavities.
Another existing prior art system for retaining small components within the carrier tape is to use an embossed plastic carrier, aka blister tape. Small tub-like cavities are thermoformed into a strip of plastic. The small components are respectively placed into the cavities, and the cavities are covered with a heat sealed cover tape. The heat sealed cover tape encloses the cavities which contain the small components.
The inherent characteristics of both punched and embossed conventional carrier tapes provide that the small components are loose in the punched or embossed cavity. While they are retained within the recess of the cavity, the small components are free to move. When the top cover tape is removed by peel back, vibrations are induced which can cause the small components to move out of their required orientation or jump out of the cavity. In addition, very small components can and will adhere to the cover tape because of static electric charge buildups generated during the cover tape peel back and thereby not be available for automatic retrieval from their cavities. Furthermore, these static electric charges, however slight, can damage or destroy active electronic components through electro-static discharge (ESD).
A classic problem with conventional carrier tapes is that the peel-back of cover tape creates adverse vibrations on the carrier tape. These vibrations are particularly troublesome with extremely small lightweight components, the position of which can be disturbed by these vibrations. Another problem is that it is impossible to heat seal the cover tapes with total uniformity. This irregular seal causes `spikes` during peel back which result in vibration and component disorientation. Vibration forces of as little as 0.05 newton have been known to cause components to jump out of their cavities or assume positions whereby retrieval using vacuum probe nozzles is not possible. In addition, static charge buildups which frequently occur when the cover tape is peeled back attract the small, light weight components which will frequently cling to the cover tape and be withdrawn from or dislodged within the carrier tape cavity. Still another problem with the cover tape is that the static charges which can build up on the cover tape during peel back can be released as a sudden burst and applied to one or more small active components such as bare die which are highly susceptible to ESD damage. Electro-static discharge applied to small components such as integrated circuit chips or die can cause reliability concerns and catastrophic failure.
Another existing prior art means for housing the small components is to use a punched paper carrier tape, as contrasted with a plastic, both used in conjunction with top and bottom cover tapes. In addition to the problems discussed above resulting from the usage of cover tape, the paper carrier tape creates problems due to dust and lint which are generated when the cover tape is pulled off the paper carrier tape surface. The paper carrier tape can delaminate when the top cover tape is pulled off, resulting in sudden separation of a length of cover tape from the carrier with subsequent component spillage. In the case of bare IC chips or die, use of paper carrier is strictly prohibited because of contamination concerns.
In another existing prior art system, the carrier tape has a multiplicity of apertures and a single length of pressure sensitive tape at the bottom and no cover tape. Small components are individually placed into the aperture of the carrier tape on the adhesive. When the components are removed from the adhesive surface, a vacuum tip is usually employed to remove and carry the component. Excessive adhesive strength in the component to adhesive bond can make separation of the component from the adhesive surface difficult. A sharp poke-up needle is sometimes used to release the component from the adhesive in coordination with the action of the vacuum tip. It is often awkward to use the poke-up needles to release the small components because the poke-up needles cannot directly engage with the small components and they sometimes exert unbalanced mechanical force to the small component as they push through the adhesive bottom. A small portion of the adhesive may adhere to the IC or other small component after it is removed from the carrier tape and the adhered adhesive causes problems when the component is placed on a printed circuit board or other mounting surface. Finally, with a film backing of pressure sensitive tape to contend with, a poke-up needle encounters considerable resistance as it tries to penetrate the adhesive backing and push the IC or other small component out of the carrier tape. Fine pointed needles are required to penetrate the film backing of the pressure sensitive tape. However, these fine pointed needles expose components to physical damage, and frequently break during repeated use, resulting in production downtime and increased probability of adhesive retention on the component.
The applicant of this application is also the inventor of the invention claimed in U.S. Pat. No. 5,203,143 issued to Gutentag on Apr. 20, 1993 for "Multiple And Split Pressure Sensitive Adhesive Stratums For Carrier Tape Packaging System", where the carrier tape utilizes two split PSA tapes, instead of one, on the bottom side of the embossed carrier tape. Adjusting the gap between the two PSA tapes provides precise adjustment of the firmness of the adhesion between the small component and the two PSA tapes. The applicant desires to develop a carrier tape system which does not utilize pressure sensitive adhesive material to hold the small components and does not require poke-up needles or other push-up tools for removal of the small components.
The following sixteen (16) prior art patents were uncovered in the pertinent field of the present invention:
1. U.S. Pat. No. 2,885,849 issued to Wohlman, Jr. on May 12, 1959 for "Semiconductor Taping Apparatus" (hereafter "the Wohlman Patent"); PA1 2. U.S. Pat. No. 3,177,629 issued to Anspach on Apr. 13, 1965 for "Apparatus for Loading Components" (hereafter "the Anspach Patent"); PA1 3. U.S. Pat. No. 3,608,711 issued to Wiesler et al. on Sep. 28, 1971 for "Package For Electronic Devices And The Like" (hereafter "the '711 Wiesler Patent"); PA1 4. U.S. Pat. No. 3,691,436 issued to Maijers et al. on Sep. 12, 1972 for "Electrical Circuit Element Having A Diagonal Abutment Strip, And Method Of Manufacturing the Same" (hereafter "the Maijers Patent"); PA1 5. U.S. Pat. No. 3,785,507 issued to Wiesler et al. on Jan. 15, 1974 for "Die Sorting System" (hereafter "the '507 Wiesler Patent"); PA1 6. U.S. Pat. No. 3,881,245 issued to Dudley et al. on May 6, 1975 for "Mounting Electrical Components On Thick Film Printed Circuit Elements" (hereafter "the Dudley Patent"); PA1 7. U.S. Pat. No. 3,971,193 issued to Tardiff et al. on Jul. 27, 1976 for "Machines For Sequencing Diverse Components" (hereafter "the Tardiff Patent"); PA1 8. U.S. Pat. No. 4,298,120 issued to Kaneko et al. on Nov. 3, 1981 for "Chip-Like Electronic Component Series And Method For Supplying Chip-Like Electronic Components" (hereafter "the Kaneko Patent"); PA1 9. U.S. Pat. No. 4,340,774 issued to Nilsson et al. on Jul. 20, 1982 for "Device for Mounting Circuit Components On A Circuit Board" (hereafter "the Nilsson Patent"); PA1 11. U.S. Pat. No. 5,343,363 issued to Greeson et al. on Aug. 30, 1994 for "SPLIT BACKED PRESSURE SENSITIVE DIE CARRIER TAPE". (hereafter "the Greeson Patent"); PA1 12. U.S. Pat. No. 4,575,995 issued to Tabuchi et al. on Mar. 18, 1986 for "Automatic Producing Apparatus Of Chip-Form Electronic Parts Aggregate" (hereafter "the Tabuchi Patent"); PA1 13. U.S. Pat. No. 4,667,944 issued to Althouse on May 26, 1987 for "Means For Handling Semiconductor Die And The Like" (hereafter "the '944 Althouse Patent"); PA1 14. U.S. Pat. No. 4,711,014 issued to Althouse on Dec. 8, 1987 for "Means For Handling Semiconductor Die And The Like" (hereafter "the '014 Althouse Patent"); PA1 15. U.S. Pat. No. 4,724,954 issued to Sillner on Feb. 16, 1988 for "System For Conveying And Guiding Components, In Particular Electrical Construction Elements Which Are Held On A Belt In A Radially Or Quasi-Radially Belted Manner" (hereafter "the Sillner Patent");
10. U.S. Pat. No. 4,406,367 issued to Bouwknegt on Sep. 27, 1983 for "Package For Electrical And/Or Electronic Components" (hereafter "the Bouwknegt Patent");
16. U.S. Pat. No. 4,778,326 issued to Althouse et al. on Oct. 18, 1988 for "Means For Handling Semiconductor Die And Similar Electronic Devices" (hereafter "the '326 Althouse Patent"); and
17. U.S. Pat. No. 4,954,207 issued to Higuchi et al. on Sep. 4, 1990 for "Apparatus For Automatically Taping Electronic Components" (hereafter "the Higuchi Patent").
The Wohlman Patent discloses a semiconductor taping apparatus. The semiconductors are taped at lateral ends by a first pair of tapes, and a second pair of tapes where the first pair of tapes face the adhesive side of the tapes in the second pair of tapes.
The Anspach Patent discloses an apparatus for loading components. These components are primarily larger components which are leaded diodes. There is a gap in the carrier where the heads of the transistors are placed but the transistors themselves are carried by having the lead sandwiched between the carrier tape and an adhesive tape.
The '711 Wiesler Patent discloses a package for electronic devices and the like, which utilizes a tape with a plurality of openings in the tape to receive a device. The device is held in place by an adhesive tape, applied from the back, which is exposed at the opening and serves as a tape stratum for holding the device in place.
The Maijers Patent discloses an electrical circuit element having a diagonal abutment strip and method of manufacturing the same. Small discrete components are interconnected by means of a strip of tape.
The '507 Wiesler Patent discloses a die sorting system which uses a strip comprised of a relatively narrow strip formed with indexing holes along one edge, and storage holes adjacent the outer edge of the strip. On the bottom side, a thin pressure sensitive adhesive tape is laminated to the strip and provides an adhesive floor, to hold the die, at the bottom of the storage holes.
The Dudley Patent discloses a device for mounting electrical components on thick film printed circuit elements. Two metal strips are attached to printed areas, adhered by electrical resistance welding for contacting electrodes.
The Tardiff Patent discloses machines for sequencing diverse components. Small electrical components are sequenced and interconnected with a tape at opposite ends of their lead portions.
The Kaneko Patent discloses a chip-like electronic component series and method for supplying chip-like electronic components, comprising a tape-like member formed with a plurality of apertures with upper and lower cover sheets that contain small chip-like electronic components.
The Nilsson Patent discloses a device for mounting circuit components on a circuit board which include apertures in the plate designed to hold by means of a friction fit.
The Bouwknegt Patent discloses a strip-shaped carrier having apertures for retaining small components. The small components are held therein by two adhesive tapes, which partially cover the apertures on the carrier. This leaves part of the component in the aperture exposed so that an ejector can engage the component to press it out of the aperture. A similar technology is disclosed in the Greeson Patent.
The Tabuchi Patent discloses an automatic producing apparatus of chip-form electronic parts aggregate. There is a tape-like housing body formed by the automatic producing apparatus. The tape-like housing body has a feed hole along the side and a frame type housing hole with a specific pitch between the housing holes. There is a tape covering which essentially covers the entire portion of the carrying tape.
The '944 Althouse Patent discloses an apparatus for handling semiconductor chips and the like objects. It includes a carrier which has a base member with an upper face covered by a pervious texturized sheet. A thin flexible sheet covers the pervious texturized sheet and extends outwardly beyond the perimeter thereof in sealing engagement with the base member. The chips are supported on the upper face of the thin flexible sheet in full surface contact with the thin sheet, and interfacial forces tightly hold the chips in position on the thin sheet. The thin sheet is drawn downwardly into interstices or crevices, in the face of the pervious texturized sheet by reducing the gas pressure at the pervious texturized sheet thereby reducing the surface contact between the chip and the thin sheet which, in turn, reduces the force by which the chip is attached to the thin sheet.
The '014 Althouse Patent discloses a method of handling semiconductor chips and the like objects. The '014 Althouse Patent is exactly the same as the '944 Althouse Patent. The '014 Althouse Patent discloses a method of attaching an object to the thin flexible sheet and drawing the portions of the thin flexible sheet into interstices between the crossovers by connection of the pervious texturized sheet to a vacuum source such that the portions of the thin sheet are withdrawn from the object, and thereby remove the object from the thin flexible sheet.
The Sillner Patent discloses a system for conveying and guiding components, in particular electrical construction elements which are held on a belt in a radially or quasi-radially belted manner. The components are also held by a tape at the ends of their leads.
The '326 Althouse Patent discloses a method and means for handling semiconductor and similar electronic devices. It includes a carrier which has a base member having an upper face formed with recess means inside the perimeter thereof. A thin flexible film is supported on the upper face of the base member in sealing engagement. The chips are supported on the thin flexible film in full surface contact with the film. To remove the chips from the film, the film is drawn downwardly into the recess means by reducing the gas pressure in the recess means thereby reducing the surface contact between the chip and the film which, in turn, reduces the force by which the chip is attached to the film.
The Higuchi Patent discloses an apparatus for automatically taping electronic components. The electronic components are placed on an elongated tape body at a regular pitch and an adhesive tape is applied to fix the electronic components in position. One of the main points of the Higuchi Patent is that the electronic component is placed on an elongated first tape and by applying a second tape, the component is fixed between the two tapes.
It is highly desirable to have a very efficient and also very effective design and construction of an improved carrier tape packaging system for receiving, retaining and releasing small components. The carrier tape does not retain small components by pressure sensitive adhesive (PSA) material, does not use poke-up needles for removal of the small components, and does not contain a top cover tape to retain components within their respective cavities. Therefore, the improved carrier tape can eliminate the problems associated with the use of PSA material, poke-up needles, and top cover tapes.